Method for the sequential provision of portions of a towel web

ABSTRACT

In a towel dispenser, a selection can be made between a standard program, in which, to form a towel loop, first a portion of unused towel and subsequently a shorter portion of used towel is released, and a hygiene program, in which only unused towel is released. In both cases, a movement sensor monitors whether the towel is moved as a result of external action, and if this is so the towel portion is drawn in as used 3 seconds after the movement has ceased. If the towel, after being dispensed, is not moved for 20 seconds, it is retracted as unused. In both cases, economy programs with a dispensing of shorter towel portions can be selected. Within the standard program, a selection can be made between a normal program, in which used towel is first drawn in and subsequently unused towel is provided, and a fast program, in which the dispensing of unused towel takes place first. Where the tripping of towel dispensing is concerned, a selection can be made between a trip by the movement sensor, which, in the state of rest, detects movements imparted to a short loop, or a trip by an infrared sensor. In the fast program, the towel dispensing takes place without a trip.

The invention relates to a method for the sequential provision ofportions of a towel web by means of a towel dispenser according to thepre-characterising clause of claim 1. Methods of this kind serve forproviding a user with towel portions for drying his hands.

There is a known method of the relevant generic type (CH-A-561,535), inwhich both used and unused towel is released automatically via a toweldispenser in response to a trip. In this system, even if the user usesthe front part of the loop consisting of unused towel, it isnevertheless very easily possible that he will also touch the used partof the towel. This is of no importance in normal hygiene requirements.However, in the medical and care sector and, for example, in industrialfood production, the hygiene requirements are considerably morestringent than at the customary locations of towel dispensers. There,the possibility that the user will come in contact with used towel hasto be preventable. Furthermore, used towel should be drawn inimmediately so that bacteria which have possibly settled on it cannotspread.

On the other hand, it is highly undesirable for economic and ecologicalreasons to use more towel web than is necessary. The aim is, therefore,even where it is perfectly acceptable if a user touches used towel, toprevent the towel loop always being formed from unused towel only.

The invention is intended to remedy this. The invention, ascharacterised in the claims, provides a method in which the toweldispensing can be adapted to particular local needs or else those whichchange in the course of time.

The advantages of the invention are to be seen, above all, in that itaffords the possibility of catering in a controlled way for specialconditions of use, particularly those with special hygiene requirements,by means of special programs which can be selected by the maintenance orassembly personnel or the manager. Even the replacement of used towelwebs by unused ones can be assisted by means of a program and thussimplified and speeded up.

When a suitable towel dispenser is employed, the programs can be sodesigned that dispensed but unused towel is retracted. In general, amore economical use of clean towel and therefore longer washingintervals are achieved, this being desirable from both economic andecological points of view.

The invention is explained in more detail below by means of Figuresillustrating merely an exemplary embodiment, a towel dispenserespecially suitable for carrying out the method also being shown indetail. Of the Figures

FIG. 1 shows a side view of the right-hand side of a towel dispenserwith towel inserted, the side wall being omitted,

FIG. 2 shows a front view of the towel dispenser, a front cover beingomitted, and

FIG. 3 shows a top view of the right-hand side wall of the toweldispenser, a lateral cover being omitted,

FIG. 4 shows, enlarged, a cutout from FIG. 1 illustrating a movementsensor,

FIG. 5 shows a circuit belonging to the movement sensor,

FIG. 6 shows a flow diagram illustrating the method according to theinvention, above all the parts run through in a state of rest beingshown in detail,

FIG. 7a shows a flow diagram illustrating in detail the steps runthrough after a trip in a standard program,

FIG. 7b shows a flow diagram illustrating in detail the steps runthrough after a trip in a special hygiene program, and

FIG. 8 shows a further flow diagram illustrating in detail the detectionof a use of the towel.

FIGS. 1 to 5 show a towel dispenser comprising, in a housing 1 mountedon a wall by means of its rear wall 2, a tiltably suspended shell 4loaded by springs 3 with an upwardly acting force and intended forreceiving an unused towel web 5 (represented by a dashed line) wound toform a roll, as well as a first transport device with a transport roller6a which is covered with knobbed rubber and which is driven from anelectric motor 9a via a worm gear consisting of a worm 7a and of agearwheel 8a connected to the transport roller 6a. A half-disc 10afastened to the worm 7a forms, with a fixed light barrier 11a detectingpassages of the half-disc 10a, a revolution counter. The gearwheel 8a isconnected to the transport roller 6a via a slip coupling which respondswhen a pull of more than 4 kp acts on the towel 5. The towel 5 ispressed against the transport roller 6a by a sprung pressure plate 12. Asecond drive device is constructed in a similar way to the first with atransport roller 6b, a worm gear with worm 7b, gearwheel 8b and electricmotor 9b and a revolution counter with a half-disc 10b and a lightbarrier 11b. For receiving used towel, a roller 13 is guided in slots14a,b in side walls 15a,b of the housing 1. The housing is closed at thefront by means of a cover 16 which is secured by a lock, so that it canbe opened only by authorised personnel for maintenance purposes,especially for a towel change. The housing 1 possesses on its sidescovers 17a,b. The power supply of the appliance is guaranteed by a powerunit 18.

The towel dispenser has a central control unit 19 which processes thesignals from various sensors and which, in particular, controls thetransport devices. To determine movements of the towel 5 caused byexternal action, the towel dispenser has a movement sensor 20 with a bar22 which is suspended rotatably in a sensor housing 21 and at the lowerend of which projects horizontally a batten 23, over the front end ofwhich the towel 5 is so guided by means of a deflecting fence 24 that,even in the non-tensioned state, because of its own weight it exerts aforce on this. The bar 22 is suspended in such a way that, in the eventof deflections, a return force occurs which ensures that it is deflectedonly a little out of its vertical position of rest by the forces exertedon it by the towel 5 at rest. Under higher forces transmitted by thetowel 5, stops 25a,b limit the deflection. Mounted in a rectangularrecess of the bar 22 is a piezoelectric element 26 which is designed asa rectangular strip and which with a first contact region is clampedfirmly at its upper edge in the bar 22 and in a second contact region inthe vicinity of its lower end is clamped between a threaded bolt 27screwed into the sensor housing 21 and a helical spring 28 coaxial withthe threaded bolt 27 and likewise fastened to the sensor housing 21. Thethreaded bolt can be adjusted perpendicularly relative to the plane ofthe piezoelectric element 26 by rotation. Since the elasticpiezoelectric element 26 provides at least some of the return force forthe bar 22, the neutral position of the bar 22 can therefore beadjusted. The output signal for the piezoelectric element 26 isprocessed in the circuit shown in FIG. 5, which essentially constitutesa limit-value detector. Under a constant bending moment, thepiezoelectric element 26 is electrically inactive. Changes of thebending moment, which are caused by movements of the bar 22 broughtabout by external actions on the towel 5, give rise to a current surge.It has been shown, in practice, that a change of the bending moment inone direction is always followed very quickly by a change in theopposite direction, so that current surges of differing sign alwayssucceed one another rapidly, and therefore only one of these need bedetected. The piezoelectric element 26 is connected in parallel to theresistors 29a,b which serve for deriving the current surge and of which29b can be varied to adjust the voltage generated by the piezoelectricelement 26, between a first voltage divider 30a and the negative inputof a comparator 31, to the positive input of which the output of asecond voltage divider 30b is applied. The voltage dividers are at asupply voltage of +5 V and are so designed that the output voltage ofthe second voltage divider 30b is somewhat lower than that of the firstvoltage divider 30a, with the result that the output of the comparator31 is normally at "zero". Now if a sufficiently strong voltage surge ofnegative polarity caused by the piezoelectric element 26 is superposedon the output voltage of the first voltage divider 30a, the voltage atthe negative input of the comparator 31 falls below the output voltageof the second voltage divider 30b applied to the positive input, so thatthe output signal of the comparator 31 jumps to "one".

An infrared sensor 32 monitors the space sector located underneath toobliquely underneath the towel dispenser for heat-radiating objects.

A rotatably suspended flap 33, around which the towel 5 is guided, isconnected to a lever 34 which activates a microswitch 35 when the towel5 is fully tensioned and presses the flap 33 completely upwards. Afurther lever 36 interacts with a further microswitch 37. The lever 36actuates the microswitch 37 when the lock (not shown) is blocked. Theblocking of the lock is only possible when the cover 16 is closed.

Between the shell 4 and the transport roller 6a, the towel 5 is guidedvia a roller 38 which has three continuous grooves 39a,b,c. A feeler 40suspended rotatably on an axle parallel to the roller 38 has threefingers 41a,b,c which are pressed against the grooves 39a,b,c under theinfluence of spring force acting on the feeler 40. When the towel endpasses the roller 38, the fingers 41a,b,c can be pressed onto the bottomof the grooves 39a,b,c, and the feeler 40 executes a rotation in theanti-clockwise direction. A lever 42 connected to it thereby actuates amicroswitch 44 via a connecting rod 43. A further microswitch 45 detectsactuations of a starting-aid button 46. All the sensors andmicroswitches are connected to the control unit 19.

A plug 47 serves for connecting the towel dispenser to a second toweldispenser of the same type normally mounted next to it.

The method according to the invention is explained below by means ofFIGS. 6 to 8.

At AA in FIG. 6, for example after the towel dispenser has been switchedon, the control unit 19 is initialised, whereupon it executes variousinitialisations and checks of further elements. Upon conclusion of theseoperations, at AB the microswitch 37 is interrogated, that is to say itis ascertained whether the cover 16 is closed and blocked. If not, it isassumed that a fresh towel web is being loaded, and the check passes onto a towel-loading program AC.

The towel change takes place, in that, first, after the complete openingof the cover 16, the roller 13, on which the used towel is wound, isdrawn forwards out of the slots 14a,b, then the shell 4 is tilteddownwards and the fresh towel roll inserted, and thereafter the towel 5is drawn through between the roller 38 and the feeler 40 andsubsequently over the transport roller 6a. The starting-aid button 46 isthen actuated, this causing approximately 1.3 m of towel to be releasedby the first transport device. The towel end is then wound around a newroller 13, and this is moved around the movement sensor 20 and the flap33 and introduced with its ends into the slots 14a,b, until it or thetowel wound on it touches the transport roller 6b. Subsequently, theflap 33 is pressed upwards and the cover 16 is closed and blocked, thisbeing recorded by the microswitch 37 and triggering a complete drawingin of the towel 5, with the exception of a towel residue, by the secondtransport device. The microswitch 35 indicates to the control unit 19that the towel 5 is completely drawn in, that is to say tensioned,whereupon the control unit stops the electric motor 9b. Thetowel-loading program AC is thus terminated, and the check passes on toAD. If it is ascertained at AB that the cover 16 is closed and blocked,the check passes directly on to AD. At AD, the state of the microswitch44 is interrogated and it is ascertained whether the towel end isreached or whether there is still a stock of fresh towel. If the towelend is reached, a pilot lamp on the housing 1 lights up and the checkreturns to AB. Thereafter, there is only a periodic check as to whetherthe cover 16 is closed and blocked or is open.

If there is still towel available, a check is conducted at AE as towhich trip mechanism has been selected for the release of towel. Thereare two possibilities here: the trip can be made by the infrared sensor32 which indicates when a person probably wanting to use the toweldispenser approaches, or by the movement sensor 20 which recordsmovements of the towel 5. In the first instance, the check passes on toAF, where it is ascertained by means of the microswitch 35 whether thetowel 5 is tensioned. If not, at AG the second transport device isactivated, until the periodic check produces a positive result. In thiscase, in the same way as with the result positive from the outset, theprogram goes on to AH, where a check is made as to whether the infraredsensor 20 responds. If not, the check returns to AB. If a trip by themovement sensor 20 has been selected, this being advisable, above all,in confined conditions to prevent faulty trips, the check passes from AEto AI, where a check is made in the way already described above as towhether the movement sensor 20 indicates that the towel has beentouched. To allow this type of trip, whenever the towel 5 has beentensioned, a piece of towel of a length of 8 cm is released by the firsttransport device, so that the accessible towel residue forms a shortloop which the user can grasp.

In the state of rest, that is to say as long as there has been no trip,the program parts described hitherto are run through periodically. Inthe event of a trip, irrespective of whether it has been caused by theinfrared sensor 32 or by the movement sensor 20, the check passes on toAJ, where the inquiry is made as to whether the towel dispenser is to beoperated according to a standard program AK or according to a hygieneprogram AL. After the execution of one of these programs, there is areturn to AB.

The standard program AK illustrated in detail in FIG. 7a begins with thestep AM, where 32 cm of unused towel is normally released by the firsttransport device. However, an economy program with a release of 27 cm oftowel can be selected. The length of the released towel portion ischecked by means of the revolution counter. One revolution of the worm7a corresponds to approximately 3 mm of towel. Subsequently, at AN,normally 15 cm and in the economy program 10 cm of used towel isreleased by the second transport device. So that the front side of theloop consists solely of unused towel, less used than unused towel isdispensed. The length check is conducted in the same way as for theunused towel. The dispensing of used towel has the advantage of savingfresh towel, whilst at the same time preserving ease of use by theprovision of a sufficiently large loop. The user will normally not touchthe rear part of the loop and therefore not come in contact with towelused by his predecessor.

In the next step AO, it is ascertained by means of the movement sensor20 whether the released towel has been used or not. This check will beexplained in detail further below. If no use is detected, at AP thereleased unused towel is retracted again completely. This step obviouslyaffords possibilities of great savings, since, especially where a tripby an infrared or other proximity sensor is concerned, faulty trips bypersons passing the towel dispenser occur very easily. In the methodaccording to the standard program, such trips without subsequent useresult in no waste of unused towel. In the following step AQ, towel isdrawn in by the second transport device, until it is completelytensioned and only a towel residue is still accessible.

If use is detected at AO, the check is first made at AR as to whetherthe towel dispenser is being operated according to a normal program or afast program. In the latter case, at AS, unused towel, once again 32 cmin the normal case and 27 cm in the economy program, is released, andsubsequently, at AT, 32 cm or 27 cm of used towel is drawn in, whereuponthere is a return to AO. In the fast program, therefore, unused towel isdispensed not only before used towel is drawn in, but also withoutwaiting for a trip. This is possible without a waste of towel onlybecause a check is made as to whether a use takes place and, in theevent of non-use, the unused towel is drawn in again, whereupon thestate of rest is then assumed. It is expedient to select the fastprogram, above all, when a crowd is to be expected.

If the normal program has been selected, at AU used towel is drawn in asfar as it will go, in the same way as at AQ. At AV, the trip mechanismis determined. If the trip is made by the infrared sensor 20, thestandard program AK is abandoned and there is a return to AB, that is tosay to the state of rest. If the trip is made by the movement sensor 20,8 cm of unused towel is released beforehand at AW in order to form ashort loop.

In addition to the standard program AK, there is a hygiene program ALwhich has been developed specially for hospitals and other environmentsdemanding especially stringent hygiene requirements, such as, forexample, food production companies, laboratories, etc. Particularimportance has been placed on ensuring that the user cannot under anycircumstances come into contact with a towel portion which has beentouched by another user. Only fresh unused towel is made accessible toeach user. Furthermore, a somewhat longer towel portion than in thestandard program is provided each time.

At AX, 64 cm of unused towel is normally released. Here too, however,there is an economy program in which a portion of a length of only 54 cmis released. Thereupon, at AY, 17 cm is drawn in by the second transportdevice, and consequently the towel residue accessible before the trip ismade inaccessible. It is ascertained at AZ whether a use has takenplace. If not, at BA, 41 cm or, in the economy program, 31 cm isretracted again, whereupon, at BB, the towel is drawn in on the draw-inside as far as it will go. Here too, therefore, the saving obtained bydrawing unused towel in again in the event of non-use is considerable,although it is not drawn in again completely. If no use is ascertainedat AZ, the towel is drawn in as far as it will go only at BC in the sameway as at BB. At all events, the check passes on to BD, where the tripmode is interrogated. In a similar way to the standard program AK, ifthe trip is made by the infrared sensor 32 there is an immediate returnto AB, whilst if it is made by the movement sensor 20, 8 cm of unusedtowel is previously released at BE, so that the accessible towel residueforms a small loop.

It should also be mentioned that, since the shell 4 is usually drawndownwards by the towel 5 when unused towel is released, to protect thesprings 3 the release always takes place in such a way that 2 cm oftowel is additionally dispensed and drawn in again immediatelythereafter. It thereby becomes possible for the shell 4 to be raised.

The detection of a use, carried out both in the standard program AK(step AO) and in the hygiene program AL (step AZ), is now explained bymeans of FIG. 8. At BF, a timer is set at a running time of 20 seconds.A check is made at BG as to whether the movement sensor 20 has detecteda movement imparted to the towel. If not, a check is made at BH as towhether the timer is still set. If so, there is a return to BG,otherwise it is determined that no use has taken place. If it isestablished at BG that the towel is being moved, at BI a further timeris set at a running time of 3 seconds, and thereupon a check is madeagain at BJ as to whether the movement sensor 20 has detected amovement. If so, there is a return to BI that is to say the timer isreset to the start of the running time. If no movement of the towel isdetected at BJ, a check is made at BK as to whether the timer is stillset. If so, there is a return to BJ, otherwise a use is determined. Theloops BG - BH BG and BJ - BK - BJ are each run through 64,000 times persecond. Since the voltage pulses generated by the piezoelectric element26 have a duration of at least a few milliseconds, any movement goingbeyond an adjustable threshold is reliably detected.

Thus, if after the formation of the loop, the towel 5 is not touched fora standby period of 20 seconds, no use is determined and the releasedunused towel 5 is retracted again completely (standard program AK) orpartially (hygiene program AL). If the towel 5 is touched, a check ismade as to whether the loop is being touched, until no movement has beendetected for a waiting time of 3 seconds. The user therefore has as muchtime as he wishes to use the towel. Only when he has not touched it forat least 3 seconds is it established that a use has taken place and isconcluded and the next step initiated.

By means of the plug 47, when it has been established at AD that thetowel 5 is used up, an adjacent identical towel dispenser can beactivated, and moreover various program parameters can be transferred,so that the second towel dispenser functions in exactly the same way asthe first (standard/hygiene program, etc).

It is also possible to provide a transmission of information betweentowel dispensers and a central station either via the power line or viaseparate lines. Thus, information on the state of the towel dispenser,especially the towel stock, can be transmitted to the central station,and conversely commands, for example for a program change-over, to thetowel dispenser.

We claim:
 1. Method for the sequential provision of portions of a towelweb by means of a towel dispenser, in which, starting from a state ofrest in which only a towel residue is accessible, a portion of unusedtowel is released in response to a trip, to form or enlarge a loophanging from a housing, and subsequently used towel is drawn into thehousing and, at least when a further trip has not occurred in themeantime, the state of rest is resumed, characterised in that aselection becomes possible at least between a standard program, in whichused towel as well as unused towel is released to form or enlarge theloop, the released portion of used towel being shorter than the releasedportion of unused towel, and a hygiene program, in which only unusedtowel is released to form or enlarge the loop and the towel residue isdrawn in.
 2. Method according to claim 1, characterised in that, in thestandard program, the release of used towel takes place after therelease of unused towel.
 3. Method according to claim 1 or 2,characterised in that a periodic check is made by means of a movementsensor (20) as to whether the loop is being moved as a result ofexternal action.
 4. Method according to claim 3, characterised in that,at least after the formation or enlargement of the loop, use isdetermined if, after a movement of the loop has been detected at leastonce, no further detection takes place during a waiting time.
 5. Methodaccording to claim 4, characterised in that the waiting time is between1 second and 5 seconds.
 6. Method according to claim 4, characterised inthat, if no use has been detected during a stand-by time, the releasedunused towel is at least partially retracted.
 7. Method according toclaim 6, characterised in that the stand-by time is between 10 secondsand 30 seconds.
 8. Method according to claim 4, characterised in that,within the standard program, a selection becomes possible between anormal program, in which, after use has been determined, used towel isalways drawn in and the state of rest assumed, and a fast program inwhich, if, after use has been determined, a further trip takes placebefore used towel has been drawn in, first unused towel is released andthereafter used towel is drawn in.
 9. Method according to claim 3,characterised in that, in the state of rest, the towel residue forms ashort loop and the trip is made as a result of the detection by themovement sensor (20) of a movement imparted to this.
 10. Methodaccording to claim 1, characterised in that, in the state of rest, thetowel residue is tensioned and the trip is made by a proximity sensorwhich detects objects located underneath or obliquely underneath thetowel dispenser.